The present invention relates to an optical alignment system applicable to an optical communication system or a laser machining apparatus and, more particularly, to an optical alignment system for adjusting the optical axes of a plurality of beams, each having a different wavelength, to a predetermined position.
With optical alignment of the kind described, it is a common practice to adjust the positions of a laser, lens, mirrors and others at the stage of production so that the optical axis of a laser beam which is adapted for communication or machining may be aligned with a desired axis. For example, in a laser machining apparatus which uses a laser beam for machining a workpiece and a visible probe beam for observing a point of the workpiece being machined and having a different wavelength from the machining beam, lenses, mirrors, and beam splitters have to be so positioned as to bring the optical axes of the two beams into alignment and thereby to cause a point being observed into coincidence with a point being actually machined. A problem heretofore pointed out is that the positions of the optical axes of the machining and probe beams tend to deviate due to the movement of optics caused by temperature variation and aging, and due to distortion of a laser medium caused by heat, resulting in poor machining accuracy.
Further, in the case of bidirectional optical communication between satellites or between a satellite and a ground station which uses light beams of different wavelengths as transmission signals, it is necessary that various structural elements be positioned with considerable accuracy because the transmitting and receiving stations are located at a considerable distance from each other. In this case, too, should the optical axis of a transmitted beam or received a beam be dislocated due to changes in the positions of a lens, mirrors and other optical elements installed in a satellite or in a ground station, communication would practically fail.